Production of high alcohols by improved oxo process



May 12, 1953 w. J. cERvr-:NY

PRODUCTION OF HIGH ALCOHOLS BY IMPROVED OXO PROCESS Filed Sept. 13, 1951 2 Sheets-Sheet 1 o ou xtc Wl Y 2, ...mi Re .U m w Mh. N e T \m mm w l X @29x00 W Etno ob W m ES@ @mi Rw .m nxcu Qnu Y l KLJ um mm. Ei :MMI W\ .w w l-, N? a M E ,S Smm w a m M N .Egon w a m m w Nw m m 9 M V wm a a 3 d O owacu 1 W 0 X u ma N mw w n x TNQ 0 O .vw -..l VOA I v M 4 W G l we IPMNIIIW Nw a www w QL w mm QN a a s J u a m ,zo u n! wm. W Y LS: W m. W W Nav u n u a. A Mw m w \N .m r W QN m NN 3 m a w Y @w f @N EB$W Co .EQQNM Nm Q May 12, 1953 w. J. cERvl-:NY

PRODUCTION OF' HIGH ALCOHOLS BY IMPROVED OXO PROCESS Filed Sept. 13, 1951 2 Sheets-Sheel'I 2 mEOtOm OXO NNN..

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Enq @33cm "lo INVENTOR Wil/iam J. Gerveny AT TORN E Y process.

Patented May 12, 1953 UNITED- William; J: oervenyg' Lansing; assigner to standard'y `oii-f company, ehieagogI-IL, scorporation-ofTldian.

Applioationseptember 13, 1'951',fSerialNo. 246333V K morenas;

.1v y l This' invention relates to improvement` pro:- ducton of' high boiling alcoliol'sV and itpertains more particularly to. improved.' methods" and meansfor producing highboi'lingi alcohols which .are substantially free from.v ald'ei'ivde's aiidfroin y other impuriti'eswhicld have .heretofore contaminatedsucnalcohols producedby'the' soscalie'd oxo This is.. a` contnuationein-parti or' copend'ing. prior.faploiication;y Serial Numberr 201W?, Ied`Ap`ri`l' I3; 19482 andnow' abandoned; Certain subject matter described herein is'. c'laiii'redl in companion application, Serial Number 246,368, in the name of. L..W. Russumand'R. J; Hengste'- .beck,. filed SenteniberV I3', lf951',.Which, in' turn, is .a continuation-:impart of'` Seriali Number 20,786,

l'edApril '13 1948, now abandoned,

theoxo processanolen, such for example asheptene or. octene,is.reactedl with lcarbon mon'- oxideandhydrogen at high. pressurein thepres'- ence.v of a carbonyl forming' metalcatalyst such ascolcaltto yieldY an aldehyde with one more carbon atom per. molecule. This reaction. is'rei'erredto as oxol'ation and" it istaccoinpaniedby side reactionswhi'cninclu'dei a certain'r amountof hydrogenationto. forni alcohols; aldehyde poltmerization. and formationof" relatively .boiling, products oi indeterminate composition. The second' step ofthe oxo process is" the' hydrogenation of productsproduced inthe first stepbrimaril'y to convert the. ald'ehyde intoalooholiafter which the hydrogenatedl. products are. fractionated into. anal'coliol fraction .(nonylalcoholiwtien the chargedolei-in is .an octene)',. a.1oWer:,l5oiling hydrocarbon fraction. and a higher boiling frac'- tion. The alcohol' fraction thusobtainedisusually discol'ored. and contaminated.. with'. ahou't'.. .5 toi 3%` of.' aldehyde and. other impurities; which are objectionable. andi' which..rende'1: the alcoliol unsuitable .fon important uses. An object of.-I this invention .is to provide .a .method and! means for producing. by amodified oxo. process. anfal'cohol which'. is not.discoloredzand'which issubstantially fiee` from aldehydesv and.' other-.impurities A further object is toprovide. improvements inthe. oxo4 process whereby product degradation is. reduced to aA minimum and" wherebyfmaxifn'um yields of`high quality productsmay be. obtained with va minimum investment andoperating costs.

`Another object is to provide imprOIedcataIst materials andimproved' methods. of V1catalyst utilization.

Another object" is to provide a. method.l and means for effecting' product hydrogenation. With 2. gen' production and punnjcaticmy may be reduced tar'riifn. Still arioter'o'bject is to' increase the effectiveness of'hydro'gen' .utilization An y important object of' thel invention is to minimize reduction of: alcohols to hydrocarbons inthe oxolation product hydrogenat'ion step and to nini'lnize' saturation orolensipresent in oxolation products; Other' objects Willb'e apparent as, the. detil'd description of the invention pro"- ceed's'.

'If/o. aceoxp1isii-the above objects a normally gaseous .hydrocarbon is reacted with steam `ina multiple. reforineil s'ijsteiii,v the' products ofthe firstv reiv'orr'ne'r.. being passed through' a' converter with additional. steam. to produ'cea; lgas consistingessent'i'all'y"of'lydiogen and carbon dioxide. This. .carbon dioxide is' sen'arated and' reacted with. hydrocarbons'. and' steam in'l the second re'- forlner to produce' carbon indiiox'icl'e'v and'hydrogen. in about' a.1':1I ratio. togetherA With carbon dioxide whionjis. separated" andlreeycled The hydrogen containing, about .2` to. 3%. or.; morel carbon monoxide wherebythe expense of'hydro- 'The lzl'rlydrogen-.r-carbon Iiloiioxde mixture `(m1-10s,asiiigias 1.3:1' may be used) is" passed through an-oxoi'ation reaetionz'one together lwith ari aliphatic. deliri-containing about?,` to" or more. earbonatoms. perf roieeule, for" example a mixture. .of .'heptenes.. or.. o'otenes, in' the presence ofl ari-. oxoltion vcatalyst suc/1'1" asf cobalt. under conditions. to. eictlsubstantial'l oxolation,v i. e. conversion..off.octene.to non'yl' al'dehy'de. Where the. charge.v isv ami'iiture offoleijlns ,obtained by polymerization\of.' a mixture' of n-butees' and isobutylene,.. the olns.. which do not react are generally characterizedlcy. highest octane. numbersandlare the; most valuable components .for motor.; fuel. iolatiol'i may. be effected. by" onerating at aboutlo p. s..i.` g; atate'mperature offagb'outZLto.KIOFQ e. gf. about33W F., with apliouid space-.velocity ofaboutf .15 to.. 1*.5r e. yg.

l about. .5 employing".aboi-it..01y to .2"01'` more.4 e3 g.

about .1l Weifglitper.. cent .catalyst ascobalt and iff-60% an aldhyde tor alcohol" ratio. of about low olen saturation (oto .10%

The liquid' product: oftle oxolltion step, after catalyst. has .been removedtherfrom. by acid Washing, may thenv be subject'edto a ist'hydro- Ahydes and other impurities.

'genation step under conditions for converting most of the nonyl aldehydes to nonyl alcohols without converting appreciable amounts of alcohols to hydrocarbons or saturating appreciable amounts of unreacted olens. This hydrogenation may be effected by trickling the oxolation product over supported cobalt catalyst, preferably about 3 to 15% or about 12% cobalt on pumice, at a temperature of about 350 to 600 F., e. g. about 450 F. and a pressure of about 850 p. s. i. g. or more in the presence of hydrogen from the final hydrogenation step. To remove the heat of hydrogenation and at the Sametime increase the conversion of aldehydes to alcohols a substantial part of the hydrogenated product may be cooled and recycled.

The hydrogenated product is then fractionated to remove unreacted hydrocarbons and particularly to remove all materials higher boiling than the desired alcohols. The alcohol product thus obtained may contain about .5 to 3% of nonyl alde- Such impure nonyl alcohol is subjected to a second hydrogenation step by trickling it over a second hydrogenation catalyst (which may also be cobalt on pumice) at a temperature of about 300 F. to 500 F. and a pressure of about 900 p. s. i. g. or more in the presence of the hydrogen produced as herein- Iabove described. A large excess of hydrogen is introduced into the final hydrogenation reactor and under the described conditions almost all of the aldehydes are converted into alcohol without appreciably reducing the alcohol to hydrocarbons.

Perhaps the small amount of carbon monoxide 4in the hydrogen, which may be in the range of about 1 to 2%, has some inhibiting effect on alco- `hol reduction and in view of such carbon monoxide content larger amounts of hydrogenating gas -are employed than would otherwise be necessary for obtaining the product of desired purity.

'However, the hydrogen from the second hydro-t genation step is thereafter employed in the first hydrogenation step wherein carbon monoxide content (which is now enhanced) appears to inhibit conversion of alcohols to hydrocarbons and to inhibit saturation of the unreacted olefins. The product produced by the second hydrogenation step is an alcohol of high purity and it is substantially free from discoloration. The use of catalysts and conditions in the second hydrogenation step may be such as to effect complete removal of aldehydes and other impurities. In

'some cases, particularly with nickel catalyst, as much as 2 or 3% of the alcohols may be reduced to hydrocarbons, but this reduces the alcohol yield and requires a subsequent distillation step.

Regardless of catalyst and severity employed jin the rst hydrogenation step, the nonyl alcohol fraction recovered from the vhydrogenated products always appears to be contaminated with excessive amounts of aldehydes and other impurities. Rehydrogenation is ineffective for obtaining a product of the desired purity in the absence of the intervening fractionation step. Apparent- The i'lrst hydrogenation reduces a substantial 'I steam to CO2 and H2.

portion of the aldehydes and thereby facilitates the fractionation Without decomposition. The fractionation step in turn removes high boiling materials, the exact composition of which is not known but the removal of which enables the production of a high quality product in the final hydrogenation step.

Some hydrogenation may be effected in the oxolation step itself and such hydrogenation may take the place of the first hydrogenation step hereinabove referred to, if the liquid products of the oxolation step are acid-washed to remove cobalt, water washed to remove acid, then steam distilled at subatmospheric pressure at a sufficiently low temperature and short contact time to avoid appreciable product degradation. In this case the heart cut subjected to nal hydrogenation preferably consists almost wholly of aldehydes and alcohols of the desired number of carbon atoms (Ca aldehydes and alcohols when heptene is the charge or C9 aldehydes and alcohols when octene is the charge) although the removal of lighter components is not as essential as the removal of the heavier, higher boiling components. In this embodiment of the invention, the final hydrogenation is preferably effected at a pressure as high as 3000 p. s. i. and it is necessary to effect cooling in the final hydrogenation step by means similar to that hereinabove described for use in connection with the first hydrogenation step.

While other hydrogenation catalysts such as copper chromite, nickel, etc., may of course be employed, cobalt-on-pumice is of particular advantage because it is not poisoned or deactivated by as much as 2 to 3% of carbon monoxide in the hydrogen stream. Nickel catalysts in general are more active hydrogenation catalysts but when they are employed in the final hydrogenation step there is a greater tendency of reduction of alcohols to hydrocarbons. The cobalt-on-pumice catalyst enables the use of the same hydrogen in both hydrogenation steps and enables the use of hydrogen containing far more carbon monoxide `than was heretofore believed to be tolerable.

The invention will be more clearly understood from the following detailed description read in conjunction with the accompanying -drawings in which:

Fig. 1 is a schematic ow diagram of a commercial plant for producing about 36,000,000 pounds per year of nonyl alcohol, and

Fig. 2 is a schematic ow diagram of a comrrnercial plant for producing octyl alcohol.

In order to produce the hydrogen-carbon monoxide lzl gas mixture and the hydrogen for the ,hydrogenation steps, a multiple gas reformer sys- `tem is employed. A mixture of steam from line I3 with additional steam from line i4 into con- 'verter l5 wherein the mixture is contacted with a conversion catalyst such as iron oxide, which may be promoted with CaO, MgO, Cr2O3 and/or other known promoters, for converting the CO and The products from the converter, after condensing and separating out '-,sulfiirhfree'f hydrocarbon gas; frontline 25 and `S'tea1'llfromi. lll'o` 26?- Gotalclda Wi catalyst in reformer 2l likewise operatingatabout "i500 toL 15603 F11 aridthe resulting productsafter cooling and separating water;-A a're then passedby fco'iripressorl to C02v absorbers!! into which leanv v solution i'sl introduced-by line 3B; Enriched solution from thes bottom of' tower' '24?- passes 'by e13land'line 201 to CO2 activator tower ZI yseth t the' carbon dioxidein this streamsuppleiiientsf-tli'e carbon dioxide fromV the stream leav- '-ing-absorberf'lc to'supplfy the'required amount'of -GOa fory reformer 2'1". By" theabov'e' procedure `''approiima'tely 1,20'63060 cubic fe'et-per^dftyf` off'an approximately 1*:l gasmixturefof H2 :C'Ois pro- 9503666 cubicj feet' per- 'day cfa gas' consist-'ingres- `lsentiallyf of" hydrogen but containing aboutl .'5'l to 3% carbon mono-:fide is producedL and discharged through'line F9;

A v-till-'rile4 the invention is" applicable'A toV the pro- 'duction of'higher alcohols` generally, e. alcohols 4'c'ontai'ning from about 4' to 16'- or' more carbon 'atoms perf'molecule; it' 'will be' descri'bein' Fig. 1 as appl-iedto the production of n'onyl alcohol In this case a: mixture of octenesi's obtained by *dif` :"'lmerization of oleiins contained' in a butanobutylene stream' b'y'means of a polymerization catalyst such as phosphoric acid on kieselguhr. The' resulting' octene's are` separated: from" higher 'boiling components by fractional' distillation. "About 2`0`5f0'gallons` perhour'v (measured at 60 or the' butylfene kdim'ercodi'mer charge' introduced" byline 33', the major'partor the' charge "being pumpedto a' pressure off3"000"p'. s'. ii g., preheated* to about 3306 F." and' introduced 'byline'fA 34 to oxolation' reactor 35 and' ai minor" portion (about '75" gallons: per hour) being' employed' for catalyst recovery" as will' hereinafter be described. "While a'variety'of catalyst'are; known to effect the oxolation` reaction, the' -preferred catalyst in! this case is cobalt which is. introduced' the 'formi of" an oil-soluble cobalt salt, preferably co- 'ba'lt naphthenatabut'whioh evidently functions ascobaltcarbonyl. Make-up" catalyst may be introduced through line' 36 as a 6`% cobalt naph A'th'enate solution but most of the catalyst'is" recoveredl from oxol'ation' 'products and` recycled as a;y cobaltv naphthenate' solution as' will" be"y herein-- afterl` described. AboutY 8B gallons per hour" of total" catalyst solution is introduced" into the oxo-` "lation' reactor' which corresponds' to about y.11 Weight per cent cobalt' based on olefin* charge. The'l hydrogen-carbon monoxide gas stream is in-y "tr'oduced into the ox'olat'ion reactor by compres- Sory 3T', this stream' being' supplemented. by' gasesv recycled by compressor" 38'I Oxolation` is' effected yat af` pressure or about'- 3G90- p. s. 1.'. g; at a' tempera'turey of about 336 F.' anda' liquid" space v`e- 1 locityV of "about .41 to= l inunp'acked tower reactor 351. unionv may be about-2% to' feet` dialnet'"en:l

"ofhigh boiling material' decreased.

assenso "oyf about to feet height; other oxolation yte':uperatures orthef'oreer ofi 25a teY 15a-'Ruinas loeJ employed' with space' velocities of the order ot abouti to; 1l. The eiluent liquid product stream from@ the;l ox'olation reactor' may consist ci 60% `unreacted oleflns,1 about 241%;` 'of noiiyl' aldehyoes, 7% nonyl-i alcohols' iid 92% -liigrierboiiling materials although with proper cutalysts'- and: operating' conditiens'tnewamcunt off. al'deliydesf maybe `increased and'` the amount The: productslleavirg the oxolationreactor throughliiiel 3595 ar'e cooled to" about" 130'o F.- in coole-r cui, and are'intrcduced into separatonll tromba/onion part of' the' separated vgases may be recycled Ilfirou'g-l'i line: t2? compressorffand the' rest' nia-y' be continuously or intermittently purged through' line 45221'. Cooling of the reactor may-loe'` eflect'ed by' recycling of cooled reactor eiluentrluids atspaced levels in the' reactor'- or by use* oi* any other cooling means knownjtottlie art.

Liquids from separator 4l are passedthrough a pressurerec'luci'ngy valve' t3 or a throttle system to Aa -lowi pressureseparator M, which may operate atabout i0- p. s. i. g. from" which gases aredis'- c'harged tlfir-'ougl'i line 45. Most of suchV gases may' be' recycled to 'the' inlet of compressor'i and the remainder may be vented:y burned, or

' utilized elsewhere;

Liquid from the' low pressure separator is then Washed' with a 5% sulfuric acid' solution which maybe introduced at the` rate of about 6G` to'v 65 gallons' per hour from' line 16. The washingmay be' effectedy in one compartment' of a `horizontal Wash drum lilprovided with' a suitable` stirrer (not shown); the other portion of theY wash drum serving. as' a separatoror'settler, but any yeile'ctiye system for mixing and separating' may fbe used. Abouti 480 gallons per hour' of the' settled' acid may bel recycled by' pump t2 the' remaining gallons' per' hour of' cobalt sulfate anda'cid' solution being introduced by' line $9' to cobalt' fecoverysystenr 5i) intowhich about 75'gallonsper hour `of hydrocabon `(ol'en' charging' stock)` is introduced by line" 5L. about' 4'0' gallons'or' more per hour` of 10% caustic solution is. introduced by line 52 and Aabout 1'5 to' 2o gallons per' hoursof naphth'enic' aci'd is introduced byv line ,5531 The cobalt recovery' system may` comprise a simple cylindrical vessel provided With astirrer tlienet reaction being a conversionw of the cobalt sulfate to cobalt naphthenate, which reaction proceeds almost` quantitatively b'ecause'the co'baltnaphthenate dssolvedlin' the introduced' hydrocarbon. The* total mixture from this vessel isv introduced by'pump 54'in't`o separator 55 from-which sodium sulfate Solution.V is Withdrawn by line 5S'. The cobalt napthena'te' solution maybe washed with Water further mixing and sep'aratingrzones (not sl'io'wn')y to remove all' sodium sulfate and any excess caustic. The solution is. then introdu'cedli'nto the oxclation reactor by' pump 5T and line 34' together'with any make-up cobalt naphth'enate thatmay be required.` V

The acidew'as'hed' product' from tanl':v il.' is introduced into Waterwash vessel 53 wherein i-tfis washed with lt'ere'd water introduced `t'lfiroug'h l shown)l and by pump' 62v to'` rst' hydrogenation reactor 32 i'n'to'` which hydrogen' isintroducd tional gas is withdrawn through line 1I.

from line 64. Hydrogenation may be effected in va single reactor or in a plurality of reactors con- Anected in parallel and it is effected by trickling the liquid over a bed or beds of cobalt-on-pumice catalyst. This catalyst may be prepared by dissolving about 35 parts by weight of heated cobalt nitrate hexahydrate in about l2 parts by weight of distilled water, adding about 50 to 60 parts by weight of pumice (about 2 to 8 mesh or 1/8 to 1/4 inch particle size), thoroughly mixing, evaporating the water, decomposing the deposited cobalt nitrate to cobalt oxide and reducing with hydrogen at about 550 to 800 F. for a period of hours. The catalyst is preferably chargedr to the reactor before the reduction step, is heated with steam to approximately reduction temperature and then reduced with hydrogen at yabout atmospheric pressure before the reactor `goes on stream. The amount by weight of cobalt based on total catalyst must be more than 3% but need not exceed 9 or 10%, about 6 to 8% being preferred. The hydrogen employed is that lwhich has previously been utilized in a subsequent hydrogenation step and it may contain about .2 to 3% of carbon monoxide (as well as small amounts of methane and alcohol) about of about 400 to 550 F., e. g. about 450 F. under which conditions most of the aldehydes are converted into alcohols, no substantial amount of the alcohols are converted into hydrocarbons, and

.a minimum amount, i. e. less than 10 or 15%, of

the unreacted olens are saturated. The liquid vspace velocity will depend somewhat upon the catalyst employed although the pumice has only 'a minor effect on the hydrogenation rate of.

nonyl aldehyde. Space velocities should be in the range of about .1 to .4 based on incoming rvoxolated liquid or about .2 to 1.2 based on total ,volumes of liquid charged per hour per volume fof catalyst space and should be such as to avoid substantial reduction of alcohols to hydrocarbons and sufficient to eect saturation of less than about 15% of the olen codimers present. Preferably the conditions should besuch as to effect about 90 volume per cent conversion of the aldehyde to alcohol.

The liquid leaving the base of the hydrogenaation reactor or reactors through line B5 may be at a temperature of about 480 to 500 F or more due to the exothermic nature of the hydrogenation. The hot liquid passes through cooler 65a and pressure release valve $6 to recycle separator 61 which may be operated at about 335 p. s. i. g. and approximately 450 F. About 5000 gallons per hour of liquid from the base of the separator is recycled by line 68 for admixture with the approximately 2200 gallons per hour of washed charge from pump 6l and the preheaters.

By thus using a recycle ratio of about 2:1 to 3:1 the temperature rise in reactor 63 may be minimized. The cooling and separation at lower pressure is essential for proper operation of pump 62. Liquids and gases from the upper part of separator 61 are Withdrawn through cooler 69 to separator 10 which may op-erate at about 335 p. s. i. g. and about 100 F. and from which addi- The 600,000 cubic feet or more per day of hydrogen withdrawn at this point may be employed vin other renery units such as hydrogenation, hy-

' was via line 68. of hydrogenation that must be eiTected in the droforming of coke still naphtha, desulfurization over cobalt molybdate catalyst, etc. Where a source of carbon monoxide is available this gas may be admixed with carbon monoxide and employed in the oxolation step.

From separator 10 the product stream passes ,through pressure reducing valve 12 to low pres- -sure separator 13 which operates at about 30 t0 f of hydrogen.

The separated product, about 2400 to 3000 gallons per hour, then passes through heater 15 and line 16 to ractionator 11 which is provided with reboiler 18 at its base. The fractionator is preferably operated at subatmospheric pressure, i. e. about 10 p. s. i. g. with a bottom temperature of about 375 F. and a top temperature of about 220 F. The overhead is cooled in condenser 19 and introduced into receiver 80 from which gases and vapors are discharged through line 8| by means of an ejector for maintaining the partial vacuum. Part of the liquid from receiver 80 is recycled as reflux through line 82 and the remainder withdrawn through line 83.

About 1200 gallons per hour of codimer gasoline is thus withdrawn from the system. y

It has been found that a side stream withdrawn from fractionator 11 between the said inlet and the top of the tower is richer in aldehydes than a stream which is being introduced into the ractionator. About 10 to 35% of the oxolation product or, in other words, about 200 to 800 gallons per hour of such side stream, is therefore withdrawn through one of the branched trap-out lines 84 and returned by pump 85 and line 85a to hydrogenation reactor The recycle of this particular material to the hydrogenation reactor oiers many advantages. It decreases the amount of aldehydes removed with codimer from the top of tower 11 and the amount of aldehydes which must be hydrogenated in the second hydrogenation step. It increases the effectiveness of the first hydrogenation reactor by decreasing the relative amount of high boiling material which would have to be returned thereto if the total recycle 1t greatly reduces the amount removed from the bottom of fractionator 11 and introduced to rerun tower 86 which is provided with reboiler 81 and stripping gas inlet 88 and from which high boiling components are Withdrawn through line 89. Stripping should be effect- U ed with an inert gas, such as hydrogen. The nonyl p. s. i. g. by pump 83 and. introduced by line 94 to second hydrogenation reactor 95. The catai lyst in this second reactor may be the same as in reactor 63 and this second hydrogenation is l preferably effected at a pressure of about 900 p. s. i. g., at a temperature of about 400 F., the .liquid space velocity being about the same as vthat employed in the rst hydrogenation, namely,

about 211:0 1.0 .volume of lliquid `per hour per volume .of Acatalyst space. The hydrogen is introduced into reactor 95 byline 19 and compressor .96, the vunused and undissolved hydrogen being'vented from the base of they reactor through line '64 for yuse in the rst hydrogenation reactor 63. .Approximately 700 gallons per hour of the impure nonyl alcohol .is thus introduced into reactor 95 yand approximately 50 to -60 cubic feet of hydrogen is introduced thereto per gallon of impure product to be treated.

'The 'hydrogenated product is cooled in cooler 91 and :introduced `through pressure ,reducing valve .98 to separator 99 vfrom 4which hydrogen is vented through `line H10 .and the final nonyl alcohol .is withdrawn through .line I'xl. The nonylfalcohol thus produced isusually of marketable .grade Without any further treatment but if the y'.nydrogenation in reactor 95 is of ysuch severity as'to reduce any alcohols `to hydrocarbons. a ysubsequent distillation step may :be .required.

.It should .be emphasized that the fractionation ,step between the two hydrogenation steps is vof .great importance because .nonyl alcohol of desired purity cannot be quantitatively obtained :by ractionating the products from the rsthydrogenation step regardless of the .severity of conditions employed therein. It Aappears that fthe oxolation reaction products contain substances which either inhibit the --action of lthe hydrogen-ation catalystfor which release further amounts of ,-aldehyde in the lrlistil-lation step. Regardless of the explanation, it has been found that a rehydrogenation after the removal of `components higher boiling than nonyl alcohol results .ina vproduct which is substantially free from a'ldchydes, color bodies or other impurities. While relatively Ipure nonyl 'alcohol can be obtained fromfthe products of the ,lirst hydrogenation step -by distillation under carefully controlled condi-tions (preferably under .greatly reduced pressure) product yields are not as high as are obtainable by rehydrogenation.

Another important feature is the utilization `of hydrogen containingas muchas .2 :to 3% ormore of carbon monoxide. The cobalt-on-pumice catalyst xhas been vfound 4to retain its activity almost indefinitely `and to be remarkably effective in reducing .aldehydes to `alcohol Without converting `alcohols to hydrocarbons. :It :is possible v.that the carbon monoxide content .of the hydrogen may itself contribute to a consider'- able Lextentto lthe selectivity of the hydrogenation which is thus effected.- Another contributing feature is the use of the large amount of hydrogen .in ,this final .-hydrogenation step, -In-uch more than would theoretically .be 'required- Much .greater product `purity is obtained by -using the `entire amount of hydrogen in .reactor y95 than could .be Aobtained by using yonly half yof the Yavailable hydrogen in this reactor and the other half :for reactor 53. By introducing .all of the hydrogenr into reactor 95 r'and then utilizing unconsumed hydrogen from reactor 195 .for

effecting hydrogenation in reactor 6.3, extremely advantageous results are obtained. The `carbon monoxide content of the hydrogen leaving reactor 85 -is somewhat greater than that of .hydrogen :introduced thereto which itself is -sur-` prising since in the hydrogenation of .butylene dimerszover nickel catalysts the carbon monoxide- .content of the hydrogen is largely converted by the catalyst to methane.

In Fig. .-2 I have illustrated a system for lthe orun r no l production 'of octyl alcohol from heptenes. The olefin :feed introduced through line 3 is a polymer gasoline which consists essentially of C to vCla oleflns and boils in the `range of about 100 to about 400 F. Such feed is introduced into fractionator f4 which is provided with conventional reboiler andvreux .means and which is operated to remove the C5 and C6 olens as an overhead vapor stream to gasoline line y6. The bottoms from fractionator 4 are introduced by line 1 .into fractionator 8 from which CB and higher olens .are withdrawn as bottoms through line 9 and added 'to rgasoline line 6. The C7 vole'lns withdrawn from the top of fractionator 8 preferably contains not more than 1% of Ce olens and not more than 12% of Cs olens. About 290 barrels .per day of such Cn olen stream is rintroduced by line 33' to oxolation reactor 35" together' with .about 430.1000 cubic feet per day of hydrogen and carbon monoxide (in :a mol ratio of 1::1 yto 1.311) through line 32 and about 31/2 barrels per day of cobalt catalyst solution through line 34'. The catalyst in this Vcase is a 6% l.cobalt naphthenate solution in C7 olefin employed in i such amounts as to provide about .1 weight per cent of cobalt based on the total Cv olens charged, but other Aoil-soluble cobalt salt may be employed.

rThe voxolation reactor is operated `at 3000 p..s. ing., about 325 F., and about .5 space velocity to obtain a 60% conversion of the olen feed; of said feed beingv reduced to C11 para-ffm, about-% being converted to Ca aldehyde., labout 8% to C8 talcohol and about 12% to polymer. The temperature control is eiected as described in `,connection with Fig. 1, about '3 or -4 volumes of product liquid being recycled for each volume of olen leed introduced. The reactor ellluent is `cooledain exchanger 38 and separated in receiver 39 into liquid and gas components. Some ofthe separated gas is vented through .line 4.0 and the remainder is recycled through line 4l by compressor Ma' for reintroduction at the point of olen inlet at the base of the reactor. A part of the :separated `cool liquid is recycled throughline 42 by pump 42a. to points Iin the reactor :above :the ,base thereof.

henet product liquid from high pressure receiver'lilr passes through release yalve d3 to .flow pressure 4separator M which operates vat about 30 p. s. i. g. vand about 100 liberated ygas beingA vented toa fuel line through line 55'. The product liquid, .about 300 barrels rper day Vcontaining approximately 1.1.4 mols per hour of aldehyde and alcohol are admired with about 10% sulfuric acid from line 46' and intimately mixed therewith with approximately one hour holding time the mixing section All. Apart of the separated acid may be continuously recycled by pump 418 While :another part is continuously withdrawn through line t9 for recovery of the vcatalyst component. Due to the reaction of about half I.of the acid to `form Icobalt sulfate, the lactual acid strength inthe acid washing andseparation stage may be only about 5%.

As .in the Yprevious example, the extract withdrawn through line li-9 is introduced to cobalt recovery sytem 50', the vcobalt being present in the extract as an aqueous. solution of cobalt rsulfate .regardless of the particularly oil-soluble cobaltsalt which is .employed in the catalyst solution. lWhile cobalt naphthenate is the preferred cobalt soluble salt, I may 4employ cobalt tallate (the cubaltsalt of acids contained .in .the tall `oil byproduct obtained paper manufacture), -cobalt stearate, cobalt oleate or any other cobalt' salt which is soluble in the hydrocarbon charged to the oxolation reactor. By contacting the extract from line 49 with an alkali metal hydroxide solution, such as sodium hydroxide, potassium hydroxide, lithium hydroxide or any equivalent thereof, in the presence of an oil-soluble acid such as naphthenic acid, tallic acids, stearic acid, or a preferentially oil-soluble carboxylic acid and also in the presence of a hydrocarbon diluent such as a part of the olefin feed to the oxolation reactor, water-soluble alkali metal sulfates are obtained and the cobalt is recombined with the oil-soluble acid which in turn is dissolved in the hydrocarbon diluent. The aqueous alkali metal sulfate can then be separated and withdrawn through line 56 while the diluted oil-soluble cobalt salt is returned by pump 51' to line 34 for further use in the process, any necessary make-up catalyst being introduced by line 36.

After catalyst removal from the oxolation product stream by acid wash, said stream is washed in mixer 58 with water introduced by line 59', the waste water being discarded through line 60. It is important in this case not only that catalyst be eliminated from the oxolation product stream but also that the product stream then be freed from acid before it is subjected to further treatment. Dilute caustic may be added to the wash water to insure that the washed product has a pH of about 7.

After acid washing to remove cobalt catalyst and water washing to remove acid, the oXolation eluent stream is passed by line |02 with steam from line |03 through exchanger |04 where it is heated to about 200 F., and thence to an intermediate level in fractionator |05 which in this case is operated at a pressure of about 180 to 220 mm. of mercury. That portion of fractionator |05 which is above the feed inlet is preferably of larger diameter than the portion below the feed inlet since it is desirable to effect as much flash distillation as possible. Thus the fractionator portion of the tower may be about 6 feet in diameter by 31 feet tall, While the stripping section is about 3 feet 6 inches by 11 feet. Additional stripping steam may be introduced at the base of the narrowed section of tower |05 through line |06. The tower should be operated with as low a pressure and with as short a contact time as is economically feasible and the tower bottom temperature should not exceed about 250 F.

Components lower boiling than C3 aldehydes (chiefly unconverted C7 and C7 olefns which have been saturated) are withdrawn from the top of the tower through cooler |01 to receiver |0111 from which about 120 barrels per day is passed by line |015 to gasoline line 6, about 510 barrels per day is returned to the top of tower |05 to serve as reflux and about 1340 to 1350 barrels per day is recycled by line |010 for admixture with streams being introduced by line |02 and |03 to preheater |04. The recycle of about 4 or 5 volumes of C7 hydrocarbons per volume of fresh feed to the fractionator-preheater makes it possible to limit the tower inlet temperature to about 200 F. and the tower bottom temperature to 250 F. and to obtain effective flash vaporization of the Cs aldehyde-alcohol components while minimizing the loss of aldehyde by aldol condensation and avoiding the mechanical difficulties in the tower which could result from the condensation of water on the trays which are employed therein if steam alone were used to meet these temperature limitations. While the recycle of C7 hydrocarbons is particularly advantageous for provid-f ing a combined heat carrier and stripping medium, other known methods may be employed for effecting flash distillation-stripping operation provided that the temperature requirements are' met so that substantially all materials higherl boiling than Cs alcohol can be Withdrawn from the bottom of tower |05 through line |08 and so that the stream which is withdrawn from a trap-out plate above feed inlet through line |09 will consist essentially of Ca aldehyde and alcohol which is substantially free from higher boiling materials. From the standpoint of product quality, it is not essential to remove all components lower boiling than Cs aldehyde. If all of the lower boiling components are retained with the Cs aldehyde-alcohol fraction, the load on the subsequent hydrogenation tower may be increased to an undesirable extent and in this example.' the heart cut withdrawn through line |09 may contain as much as 10 or even 20 mol per cent o C7 hydrocarbons (chiefly olens).

By lthe intermediate fractionation step about barrels per day of C8 aldehyde-alcohol (containing about 10 to 20% C7 hydrocarbon) is withdrawn for hydrogenation. This fraction is heated in reactor furnace |0 together with make-upl and recycled hydrogen from line |09a and introduced into reactor which in this case is operated at a pressure of 3000 p. s, i. g. and at a temperature in the range of 350 to 550 F., e. g. about 450 F. The catalyst is preferably 3 to 15%, e. g.v about 12% cobalt on pumice. With a fresh feed liquid space velocity of about 0.1 to 1.0, e. g. about .25, the olens are completely saturated and the hydrogenation of the aldehydes is substantially complete. The hydrogenation reactor eiiluent isv withdrawn through line I2, cooled in exchanger' I I3 and introduced into separator I |4 from which separated hydrogen is Withdrawn by line ||5, vent line |lo` being usually closed. The cooled hydrogen is compressed by compressor ||1 and returned by line H8, manifold ||9 and spaced inlets |20 to prevent a temperature rise of more than 25 F. in any part of the reactor. About one volume of the cooled liquid product withdrawn through line |2| is recycled by pump |22 and linev |23 for each volume of heart out fraction introduced by line |09. In this case about 16 mols per hour of fresh hydrogen is introduced by line |09a.

The net hydrogenation product passes through pressure reducing Valve |24 and is introduced into low pressure separator |25 which is maintained at about 30 p. s. i. g. and at about 125 F. Liquid from this separator is introduced through line |21 to fractionator |28 which is provided with usual reboiler and reflux means and materials boiling lower than oxo alcohol (chiefly hydrogenated olens) are taken overhead through line |29 to gasoline line 6. Bottoms from tower |28 are introduced by line |30 into final fractionator |3| for removing oxo bottoms through line |32 from the final oxo alcohol (octyl alcohol in this case) which is taken overhead through line |33. The iso-octyl alcohol thus produced boils from about 360 to 370 F., has a flash point of about 180 F., is water white, has an aldehyde content which is less than about 2%, may contain a slight amount of iso-heptyl alcohol and' iso-nonyl alcohol, depending upon the eiciency of the fractionation of the original olen feed, but the iso-heptyl alcohol content usually does not exceed .2% and the iso-nonyl alcohol usually does not exceed 2.0%.

While I have described in detail a specific exl leaving said second step sgreater than that of the hydrogen entering said step and employing the carbon-monoxide vcontaminated hydrogen from the second contacting step as the hydrogenation gas in the first contacting step.

3. In the process of producing alcohols by reacting -aliphatic olefins having in the range of 3 to 15 carbon atoms per molecule with Va carbon monoxide-hydrogen gas having a mol ratio of about 1:1 in the presence of a cobalt catalyst under conditions for converting a substantial portion but not all of the olens into aldehydes having one more carbon atom per molecule than the oleins and subsequently converting most of said aldehydes to alcohols in the presence of unreacted olens in a liquid stream, the improved method of operation which comprises removing cobalt catalyst from 4said liquid stream containing said aldehydes and unconverted olefins, then hydrogenating said stream under conditions lfor effecting conversion of most of the aldehydes to alcohols without converting any substantial amount of alcohols to hydrocarbons and without saturating the major portion of the unreacted oleflns, fractionating the eiliuent liquid stream from said first hydrogenation step for removing materials higher boiling and lower boiling than hydrogenated aldehydes and subsequently hydrogenating the hydrogenated aldehyde fraction in the absence of `said higher and lower boiling components under conditions for increasing the purity of the resulting alcohols, said subsequent hydrogenation step being effected in the presence of a hydrogenation catalyst under a pressure of at least about 500 p. s. i. g. and at a temperature in the range of about 350 to 550 F.

4. The method of producing nonyl alcohols which comprises reacting a mixture `of octenes with a carbon monoxide-hydrogen gas having ya mol ratio of about 1:1 in the presence of a cobalt catalyst at a pressure of about 3000 p. s. i. g. at a temperature of about 330 F., removing catalyst from the reaction products, then contacting said reaction products with a hydrogenation catalyst consisting essentially of cobalt-on-pumice and containing about 3 to 15% cobalt in a first hydrogenation zone at a ternperature of about 350 to 550 F. and a pressure of at least about 850 p. s. i. g. with a hydrogen gas containing an amount of carbon monoxide in the range of about .2 to 3%, reducing the pressure on the hydrogenated products and separating gases therefrom, then distilling said products for removing therefrom components both higher boiling and lower boiling than nonyl alcohols in order to obtain a crude nonyl alcohol stream, and hydrogenating -said crude nonyl alcohol stream in a second hydrogenation step with a hydrogen of lower carbon monoxide content than the hydrogen employed in the first hydrogenation step for producing substantially pure nonyl alcohols.

5. The method of claim 4 which includes the step of introducing a large excess of hydrogen containing a small per cent of carbon monoxide into said second hydrogenation step, operating said second hydrogenation step at a higher pressure than the first hydrogenation step and employing said pressure difference for introducing hydrogen containing a larger per cent of carbon monoxide from said second hydrogenation step to said first hydrogenation step.

6. In the process of producing alcohols by reacting in a first conversion zone aliphatic olens having in the range of 3 to 11A carbon atoms per molecule with a carbon monoxide-hydrogen gas having a mol ratio of about 1:1 in the presence of a cobalt catalyst under conditions for converting a substantial portion but not all of the olefins into aldehydes having one more carbon atom per molecule than the olefins while at the same time causing the formation of high boiling materials, in which process at least a part of the aldehydes are hydrogenated prior to a final hydrogenation step, the improved method of operation which comprises removing all cobalt catalyst from the liquid products leaving said rst conversion zone by scrubbing said products with sulfuric acid whereby hydrogenation may be effected in the absence of. dissolved cobalt carbonyl contained in said liquid products, fractionating liquid products prior to a nal hydrogenation step to separate therefrom at least a portion of unreacted low boiling olens and substantially all of said higher boiling materials and effecting final hydrogenation of only that portion of the product stream from which lower boiling olefins and substantially all high boiling materials have been separated by contacting said portion with a hydrogenation catalyst consisting essentially of cobalt on pumice and containing more than 3 per cent cobalt in a final hydrogenation zone with a hydrogen gas containing a small amount but less than 3 per cent carbon monoxide under a pressure of at least about 500 p. s. i. g. and at a temperature of about 400 F. to about 550 F.

7. The process of claim 6 wherein the reaction in the first conversion zone is effected under conditions to convert .about 40 to 60% of said olefins chiefly into aldehydes and alcohols containing one more carbon atom than said oleins, at least about one-fifth thereof being alcohols.

8. The method of claim 6 which includes the step of subjecting liquid product, after the sulfuric acid Washing step, to a hydrogenation prior to said fractionating step.

9. The method of claim 6 wherein at least a part of the aldehydes formed in said first conversion zone are hydrogenated in said first conversion zone and a liquid product steam from said zone, after said sulfuric acid washing step, is fractionated by flash distillation and steam stripping at reduced pressure.

10. The method of producing an alcohol which comprises reacting in a first conversion zone an aliphatic olefin having more than three carbon :atoms per molecule with a carbon monoxidehydrogen gas having a mol ratio of about 1:1 lin the presence of a cobalt catalyst under such conditions that about 40 to 60% of said olefin is converted chiefly to `aldehydes and alcohols formed by hydrogenation of aldehydes, a minor amount of the olef'lns being converted into higher boiling materials, removing cobalt from the liquid product thus produced by washing said product with sulfuric acid, removing acid from acid-washed liquid, subjecting the washed liquid to flash distillation and steam stripping at reduced pressure to effect removal of substantially lall components higher boiling than lsaid alcohol, effecting final hydrogenation of only that portion of the product stream from which high boiling materials have been separated, said final hydrogenation being effected by contacting the separated aldehyde-containing fraction from the flash distillation step with a hydrogenation catalyst in the presence of excess hydrogen gas containing a small vamount but less than 3 per cent carbon monoxide under a pressure of at least about 500 p. s. i. g. at a temperature of about 350 to 550 F. and at aspace velocity in the range of about .01 to 1 and .fractionating the products of the nal hydrogenation to obtain a substantially pure alcohol;`

11. The method of claim 10 which includes the step of removing at least a -part of components lower boiling than the aldehydes as well as lsubstantially all materials higher boiling than said alcohols in the ash distillation step whereby a heart cut consisting chieiiy of alcohols and aldehydes is subjected to the nal hydrogenation step.

12. The method of claim 10 wherein the hydrogenaton catalyst is about 3 to 15 percent cobalt deposited on pumice.

J. CERVENY.

18 References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,464,916 Adams et al Mar. 22, 1949 2,504,682 Harlan Apr. 18, 1950 2,530,989 Parker Nov. 21, 1950 2,525,354 Hoog et al Oct. '10, 1950 OTHER REFERENCES 

1. THE METHOD OF HYDROGENATING ALDEHYDES IN A LIQUID STREAM WHICH ALSO CONTAINS LOWER BOILING OLEFINS AND COBALT CATALYST, WHICH METHOD COMPRISES FIRST FREEING SAID STREAM FROM COBALT CATALYST, THEN HYDROGENATING SAID STREAM IN THE PRESENCE OF A COBALT-ON-PUMICE CATALYST CONTAINING ABOUT 3% TO 15% COBALT IN A FIRST HYDROGENATION ZONE AT A TEMPERATURE OF ABOUT 350 TO 550* F. AND UNDER A PRESSURE IN THE RANGE OF ABOUT 500 TO 3000 P. S. I. G., WITH A HYDROGENATION GAS CONTAINING AN AMOUNT OF CARBON MONOXIDE IN THE RANGE OF ABOUT .2 TO 3% AND SUFFICIENT TO INHIBIT HYDROGENATION OF OLEFINES AND CONVERSION OF ALCOHOLS TO HYDROCARBONS, FRAC- 